Building the sanitizer using the 12v DC motor / Solenoid Valve, input voltage to Motor / Solenoid Valve and MCU is from the same circuit.

Whenever MCU - digital pin D7 triggered, max load is used by the Solenoid Valve / motor and MCU is going into off state, please suggest how to proceed?

 

hi mb,
Welcome to AAC,
R15/D7 drawing error, shorted to 0V
Add a snubber R/C across the Solenoid coil.
E

 

Another drawing error: relay coil should connect to 12V, and the diode is reversed.
To fix the problem you might try a diode between 12V and C11/7805 junction. Feed the relay and solenoid direct from the 12V.

 

Of course, there may be errors in the drawing. However, if the drawing is correct, and D7 is an output that idles low, MCU should run. Setting it high creates a short to ground, which could be what shuts the MCU down.

At this point, the TS needs to submit an accurate schematic.

 

That schematic is ridiculous . There is no power connection to either the relay or the solenoid.

Bob

 

It was my mistake, Schematic was completely wrong, below find the updated Schematic. The issue is, power to MCU and Solenoid Valve / 12 V DC Motor is from the same source, whenever the D7 is High, Solenoid Valve / 12 V DC Motor starts and MCU goes on offline state.

 

hi bm,
I would add some extra decoupling caps, say 100nF close to the power pins of the Atmega, also on the Input and Output side of the 7805 reg.
E

 

Add a diode:

 

Why are you using a relay to pick up a solenoid valve on the same supply?
Why not just use a logic level FET and pick up the solenoid directly?
Max.

 

Thanks All for the responses.

I will split the power source into 2, for MCU and Solenoid Valve separately, which I believe should resolve my issue.

 

Thanks All for the responses.

I will split the power source into 2, for MCU and Solenoid Valve separately, which I believe should resolve my issue.

So do you still intend using the relay?
If so what is the reason? Just curious?
Max.

 

Very true, Relay is not required. It can be achieved by using Logical FET or Optocoupler.

Thank you very much for your suggestion.